*4.8. Microbial Analysis*

The microbial growth in samples during storage was evaluated by counting the total number of aerobic bacteria and total fungi (yeast and mold). Ten g of the sample was taken aseptically from each treatment and transferred into sterile plastic bags with 30 mL of 0.1% peptone in water. The materials were homogenized in a Stomacher blender (Thomas Scientific, Swedesboro, NJ, USA) and filtered to obtain the sample stock for microbial analysis. Dilutions were done using 0.1% peptone water prior to plating.

Total aerobic bacteria counts were determined by inoculating 100 µL of the diluted extract on the surface of plate count agar (PCA; Becton Dickinson, NJ, USA). The plates were incubated at 37 ◦C for 24 h. Total fungi counts were determined using the surface inoculation of potato dextrose agar (PDA; Becton Dickinson, NJ, USA), supplemented with ampicillin to control bacterial growth. The plates were also incubated at 30 ◦C for 48 h [11]. Afterward, the colonies were enumerated, and the results were expressed as the logarithm of colony-forming unit per mL (Log CFU g/mL) of sweet potato.
